1. Field of the Invention
This invention relates to a fault diagnosis apparatus for mounting on a vehicle, which stores conditions of abnormality of an electronic control apparatus to control a vehicle and diagnoses the fault.
2. Description of the Related Arts
There have been developed techniques which provide means for storing not only time of occurrence of abnormality and signals representing abnormalities but also the operating condition before and after the abnormality occurrence of an electronic control system or sensors of the electronic control system, and supply information on the abnormality to put the information to good use in repairs in a repair shop, for example (e.g. JP-A-61-255411 and JP-A-63-88423).
Even with the prior-art techniques mentioned above, however, when a test is conducted by reproducing the operating condition of the vehicle when abnormality occurred, it is necessary to make the operating conditions of some items same as those recorded at the time of abnormality occurrence. For this purpose, the driver is required to have the skill to make the operating conditions of the items under test identical with those at the time of actual abnormality occurrence. In addition, it is not easy to know whether or not those operating conditions of the vehicle have actually been reproduced, which difficulty has been a problem.